This invention relates to fiber optic connectors, and more particularly to a device, in the nature of a hand-held rod, for both cleaning and/or polishing the sides and end face of a ferrule of a fiber optic connector and the corresponding end face of an optical fiber contained within the ferrule.
A fiber optic connector typically includes a cylindrical ferrule which confines the transmission glass portions of a fiber optic cable. The ferrule represents a termination point, or one end, of the fiber optic cable. The ferrule typically comprises ceramic, zirconia or polymer material, or a suitable metal, such as stainless steel. Generally, the ferrule is mounted to the end of the fiber optic cable by first removing, or "peeling back", a portion of the outermost structure of the fiber optic cable. The "outermost structure" is that part of the cable which surrounds and protects the innermost optical core and cladding glass material (hereinafter together referred to as "the optical fiber") during normal usage. A typical diameter for the optical core glass is eight microns, while a typical diameter for the optical cladding glass, concentrically surrounding the core glass, is 125 microns. On the other hand, the overall diameter for the cable outermost structure in one commercially-available embodiment is 4.5 mm.
The outermost structure may comprise several outer concentric layers, including a silicone coating surrounding the glass cladding, followed by a buffer jacket. Next may be a concentric layer of strength members, followed by an outer polyurethane jacket.
Optical signals are propagated through the optical fiber during information transfer. A plurality of separate fiber optic cables may be connected together, as part of a large communications network. The cables transmit voice, video and other types of data, in the nature of electromagnetic light wave signals, between various electronic devices. Fiber optic cables are generally terminated at interfaces with other fiber optic cables at splices or at pieces of electronic signal amplifying or "booster" equipment. Alternatively, fiber optic cables may terminate at an interface with light transmitting and/or receiving devices.
The termination or end face of the ferrule also generally includes the termination or end face of the optical fiber, usually both in the same plane. The ferrule of one connector is typically aligned and mated with the ferrule of another connector at a junction point, thereby aligning the optical fibers within both ferrules.
In the art of fiber optic connectors, such connectors are generally arranged structurally such that there are at least two types of relationships of ferrules with respect to an associated connector adaptor. A first "male" type has the end point of the ferrule protruding beyond or equal to the corresponding end point of the connector adaptor, and the ferrule also forms a crevice or air space between the outer surface of the ferrule and the inner surface of the connector adaptor. A second "female" type has the end point of the outer connector adaptor protruding beyond the corresponding end point of the ferrule, such that the end face of the ferrule is in a recessed position with respect to the connector adaptor.
For relatively maximum optical signal transfer between two mated or adjacent optical fibers, it is extremely important to keep the connector and all its components clean, especially the ferrule end face and side. It is particularly important to keep contamination off the ferrule end face where the exposed end of the optical fiber is located. Any contamination (e.g., fine dust or dirt particles, grease) at this critical interface point interferes with the propagation of light energy out of one optical fiber end and into another. Although the sides of the male-type ferrule do not touch the optical fiber, contaminants from the sides and the recesses of the connector adaptor and housing could ultimately gravitate to the optical fiber end face and cause interference or loss in coupling of optical energy between adjacent optical fibers. Thus, it is important to keep contamination off the sides of a male-type ferrule as well as off the end face. Also, for female-type ferrules, contaminants could ultimately gravitate from the inside surfaces of the connector adaptor over to the optical fiber end face.
Prior art ferrule cleaning devices consist of a multitude of wipes, air sprays and cleaning fluids. However, none of these specifically address cleaning of the side of the ferrule. Also, they do not reach down into the crevices of the adaptor, nor do they wipe, with any degree of consistency, the complete ferrule side and the crevices all at once. A further problem is that, in many types of connectors, the ferrule is permanently embedded in an assembly, cannot be removed and is not easily accessible; one example is the plug assembly of the SC connector produced by Siecor Corp. of Hickory, N.C. Therefore, known prior art ferrule cleaning devices are inadequate for cleaning the sides of a male-type ferrule.
Accordingly, it is a primary object of the present invention to provide a simple, hand-held device, in the nature of a rod, that cleans the sides of the male-type ferrule, down to the base of the ferrule located in the housing of a fiber optic connector.
It is a general object of the present invention to completely clean the sides and end face of a male-type ferrule to significantly reduce, or even eliminate, the possibility of any contaminants migrating from the sides of the ferrule onto the end face of both the ferrule and the optical fiber to thereby degrade or impede signal transmission into or out of the optical fiber.
It is another object of the present invention to provide a device for cleaning the sides of a male-type ferrule and the crevice created by the juncture of the ferrule and the connector adaptor used with single and multiple fiber optic connectors, wherein the ferrule is exposed or encased in various connector adaptors or sleeves.
It is another object of the present invention to provide a device for cleaning and/or polishing the end face of a female-type ferrule and the corresponding end face of an optical fiber within the ferrule.
Still another object of the present invention is to provide a device for cleaning and/or polishing the end face and sides of a male-type ferrule and the end face of an optical fiber.
The above and other objects and advantages of the present invention will become more readily apparent when the following description is read in conjunction with the accompanying drawings.